Fuse link



L. P. BOLL June 26, 1934.

FUSE LINK Filed nay 17. 193s Patented June 26, 1934 PATENT OFFICE FUSE LINK Lester Pierce Boll, University City, Mo., assigner to W. N. Matthews Corporation, St. Louis, Mo., a corporation of Missouri Application May 17, 1933, Serial No. 671,450

y 8 Claims.

This invention relates to fuse links, and with regard to certain more specific features, to fuse link heads.

Among the several objects of the invention may be noted the provision of a fuse link having a head which is universally adaptable to the various contacts associated with various cartridges now on the market; and the provision of a link of theclass described which is simple to manufacture and to apply. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing, in which are illustrated several of various possible embodiments of the invention,

Fig. l is a longitudinal section of a cartridge showing the fuse link applied to one form of contact;

Fig. 2 is a side elevation of the upper end of the link of Fig. 1;

Fig. 3 is a fragmentary view similar to the top portion of Figure 1, but illustrating a modified use of the link;

v Fig. 4 is a view similar to Fig. 3 showing another modified use;

Fig. 5 is a view similar to Fig. 4 showing another modified use;

Fig. 6 is a View similar to Fig. 5 showing another modified use of the device;

Fig. 7 is an end View of the part of Fig. 2, showing certain bending features, and;

Fig. 8 is a View similar to Fig. 7 showing certain shearing features. y

Similar reference characters indicate corresponding parts throughout the several views of the drawing.

Referring now more particularly to Fig. 1, there is illustrated at numeral 1 a fuse cartridge having Y a lower terminal engaging element 3 in which is a recess 5 into which the lower end 7 of the fuse link is adapted to be inserted and held by means of a fastener 9.

At the upper end of the cartridge 1 is attached u a second terminal engaging element ll which is sometimes formed with a diaphragm 13 through which an opening 15 permits application from above of the fuse link. l

A counterbore 17 is threaded to receive a cap 19 for holding the upper end of the link.

The link itself comprises a main body portion 2l, preferably composed of braided copper pigtail or like wire in order to effect flexibility, and a head 23. The head 23 and the body 21 are joined by means of a calibrated fusible element 24 consisting of a strip 25 of material such as tin, and a wire 27 such as of nichrome, the wire and strip being connectedin parallel. The nichrome wire has a mechanical strength which is higher than that of the strip of tin 25. The current flowing over the wire and strip divides inversely as the resistances, and said resistances are such that the tin strip 25 fuses before the nichrome wire 27, the nichrome wire 27 then fusing after the fusing of the tin strip 25 has occurred.

Thus, in the cold condition, the nichrome wire takes mechanical stress, but upon heating the same soon parts after blowing out the tin strip because all of the current flows through the wire after the strip parts. Thus the body portion 21 of the link is released and falls out of the cartridge 1 to clear the circuit of excess current. As shown, the strip 25 and wire 27 are soldered in parallel to the body 2l and likewise are soldered to the head 23. Ii will be understood that in some applications of the invention either the nichrome wire or the strip alone may be used as a fusing element.

The head 23 per se comprises a strip 29 of conducting material such as copper bent as at 31 at a hair pin turn whereby adjacent legs 33 of the strip 29 are formed. At the upper ends, the legs 33 are bent laterally and in opposite directions to .form ears 35. Between the point of attachment with members 25 and 27 and the ears 35, adjacent notches 37 are formed through the legs 33, the same being each in one edge of a respective leg. The notches 37 effect lsections 28 in the legs 33 which sections 28 are weaker in bending than the remainder of said legs but strong enough to resist the tensile stresses to be applied.

To apply the link to the contact shown in Fig. 1, the end 7 and body portion 21 are fed through the opening 15, also the fusible elements 25 and 27, and the legs 33 of the head 23. If the open- 100 ing 15 is small enough, the ears 35 lie upon the diaphragm 25, whereupon the cap 19 may be screwed home to properly seat the ears 35 to form a proper electrical contact. The lower end 7 is electrically connected by means of the fas- 1'05 tener 9. Thus the link is positioned within the cartridge and the ends thereof properly held.

In Fig. 3 is shown the head 23 applied to a cap and plug type of cartridge in which the main bore 38 extends directly up through the cap 39 110 and is covered by an exteriorly threaded cap 41. In this form, the bore 38 is often so large that the ears 35 will pass through when adjacently located as in Fig. l, or at least, will not be properly seated upon the end of the plug 39. In such event, the legs 33 may be spread to the V-shape 43, the same bending at the weaker sections 28.

Some cartridge ends are made as shown in Figiue 4 wherein the plug 45 is held in the end of the cartridge and the opening for applying the link extends farther into the cap 47. The use of the link in this application is analogous to that shown in Figure l.

In Figure 5 is shown another application of the device in which a head 49 of a cartridge is accommodated, said head having a blind recess 48 therein. The application is made by turning the ears 35 from the dotted line positions shown in Figure 7 to the solid line positions. The fuse link is then applied from the bottom of the cartridge, as indicated by the arrow in Figure 5, the holding plug 51 being at this time loose and subsequently tightened when the head 23 is in position (dat) upon the anvil 53.

In Figure 6 is shown still another application of the device to the type of cartridge wherein a plug 55 screwed into the end of a cartridge 1 carries an interior lug 57 having a. seat and holding screw 59. In this application the ears 35 and parts of the legs 33 are cut oi along a line such as A shown in Fig. 8, thus to provide clearance whereby the shank of the holding screw 59 may be applied to the notches 37 and tightened down. This application is made when the plug 55 is loosened and removed from the end of the cartridge. Then, the link is fed through the cartridge and finally, the plug screwed home. rThereafter, the other end of the link is fastened to the Contact 3.

The invention has the advantages that the ductile, two-tined head may be sheared and/or bent to accommodate it to different receiving structures. The notches 37 at once provide means for making the Fig. 6 application and also provide the weakening for effecting predetermined bending, the bending permitting lateral adjustments to various heads. By limiting the bending to occur above the hair pin turn 3l, all danger of weakening the solder connection at 31 by bending is avoided.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above descriptions or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A fuse link having a universal head, said head comprising adjacently located legs, laterally extending ears on said legs, and having adjacently located notches in said legs.

2. A fuse link having a universal head, said head comprising adjacently located legs, laterally extending ears at the ends of said legs, and having adjacently located notches in said legs, said legs being continuous and joined at a hairpin turn and being bendable, whereby they may be held to contact with various seats.

3. A fuse link having a universal head, said head comprising adjacently located legs, lateral extending ears at the ends of said legs, and having adjacently located notches in said legs, said legs being continuous and joined at a hair-pin turn and being bendable, whereby they may be held to contact with seats of various character, the same being ductile enough to be sheared for application of said notches to holding elements of certain fuse holders.

4. A fuse link having a universal head, said head comprising adjacently located legs, laterally extending ears at the ends of said legs, and having adjacently located notches in said legs, said legs being joined at a hair-pin turn and being locally bendable adjacent to said notches.

5. A fuse link having a universal head, said head comprising continuous but adjacently located legs, laterally extending ears at the ends of said legs, and having adjacently located notches in said legs, said legs being permanently bent at a hair-pin turn, the remainder of the links being fastened at said turn.

6. A fuse link having a universal head, said head comprising continuous but adjacently located legs, laterally extending ears at the ends of said legs, and having adjacently located notches in said legs, said legs being permanently bent at a hair-pin turn, the remainder of the links being fastened at said turn, the head being ductile enough whereby bending of the ears to adjacency, shearing below the ears and bending adjacently to the notches may be effected.

7. A fuse link having a universal head, said head comprising at least one leg, a laterally extending portion on said leg whereby the leg may be fastened to a seat, said leg having a notch therein, said laterally extending portion being fastened by means ductile enough to be sheared so as to remove said means, whereby application may be made of said notch to holding elements of certain fuse holders.

8. A fuse link having a universal head, said head comprising at least one leg, a laterally extending portion on said leg whereby the leg may be fastened to a seat, said leg having a notch therein, said laterally extending portion having a ductile fastening with respect to the leg so it may be bent to an alternate position or removed, whereby application may be made to other types of fuse holders.

LESTER PIERCE BOLL. 

